public class Leetcode211Workdictuibary2 {

    private class Node {
        public boolean isWord;
        public Node[] next;

        public Node(boolean isWord) {
            this.isWord = isWord;
            next = new Node[26];
        }

        public Node() {
            this(false);
        }
    }

    private Node root;

    /** Initialize your data structure here. */
    public Leetcode211Workdictuibary2() {
        root = new Node();
    }

    /** Adds a word into the data structure. */
    public void addWord(String word) {
        Node cur = root;
        for (int i = 0; i < word.length(); i ++) {
            char c = word.charAt(i);
            if (cur.next[c-'a'] == null) {
                cur.next[c-'a'] = new Node();
            }
            cur = cur.next[c-'a'];
        }
        cur.isWord = true;
    }

    /** Returns if the word is in the data structure. A word could contain the dot character '.' to represent any one letter. */
    public boolean search(String word) {
        return match(root, word, 0);
    }

    private boolean match(Node node, String word, int index) {
        if (index == word.length()) {
            return node.isWord;
        }

        char c = word.charAt(index);
        if (c != '.') {
            if (node.next[c-'a'] == null) {
                return false;
            }
            return match(node.next[c-'a'], word, index + 1);
        } else {
            for (int i = 0; i < 26; i ++) {
                if (node.next[i] != null && match(node.next[i], word, index + 1)) {
                    return true;
                }
            }
            return false;
        }
    }

    public static void main(String[] args) {
        Leetcode211Workdictuibary2 main = new Leetcode211Workdictuibary2();
        main.addWord("bad");
        main.addWord("dad");
        main.addWord("mad");
        System.out.println(main.search("pad"));
        System.out.println(main.search("bad"));
        System.out.println(main.search(".ad"));
        System.out.println(main.search("b.."));

    }

}

/**
 * Your WordDictionary object will be instantiated and called as such:
 * WordDictionary obj = new WordDictionary();
 * obj.addWord(word);
 * boolean param_2 = obj.search(word);
 */
